On floppy media that was not sold as preformatted, the unformatted capacity was commonly stated. ~2 MB is the unformatted capacity of what is commonly called a ‘1.44 MB’ floppy.
However, the actual low-level format on the floppy could be:
- PC DD format, which is 360 or 720 KiB. A PC drive can physically read that.
- Mac 800kB/400kB format. A non-specialty PC drive will choke on it.
- PC HD format. 1440 KiB. PC drive can read.
- PC specialty formats, like 1720 KiB. Unlikely that someone wrote to such a floppy from a Mac. PC drive can read with luck (these formats traded capacity for reliability) and an OS that supports it.
The filesystem could be:
- a DOS style FAT filesystem (any Windows or Linux PC can deal with that)
- a Mac-specific filesystem (MFS, HFS, HFS+) - will need extra software in Windows, and manual/special handling in Linux (a floppy automounter, if present, will likely not work).
Unless they are plaintext (and even then, you might need a text editor that is configurable regarding character and newline encoding), you will need whatever software can process the given format.
In case of a documented, or semi-plaintext, format, you might be able to write a rudimentary decoder yourself.
If the filesystem is Macintosh specific, it is important to know that these filesystems actually treat files as a pair of two "subfiles", so called forks. Macintosh applications often made use of that, and a file is incomplete and probably unusable if one of these forks is lost. Special attention has to be paid when handling this kind of file, since some non-Mac drivers will either only give you one of these forks or present them as two separate files (sometimes with one of them as a hidden file).